重穗型杂交水稻籽粒灌浆过程中强势和弱势颖花内源IAA、ABA和GA水平的动态状况

研究了重穗型杂交水稻培矮 6 4s/E3 2的灌浆过程和强、弱势颖花中内源IAA、ABA和GA1 GA3水平的动态状况。籽粒发育过程中不同内源激素水平高低依次为 :IAA >GA1 GA3>ABA。IAA和ABA水平在强势颖花中较高而GA1 GA3水平在弱势颖花中较高。 3种激素水平的变化与谷粒增重速率之间均存在正相关 ,两个最高的相关系数值分别存在于单位鲜重样本的IAA含量(ng/gFW ) 与籽粒鲜重的增重速率之间 (r =0 .82 1 8 )和单个籽粒IAA含量 (ng/grain)与籽粒干重的增重速率之间 (r =0 .8485 )。推测启动和维持籽粒灌浆过程可能需要较高的IAA水平 ;ABA可能具有促进籽粒中同化物的累积和种子成熟的作用 ;GA1 GA3可能具有保持弱势颖花活性的特殊作用     

芝麻灌浆特性与灌浆期籽粒中内源激素含量变化研究

在大田栽培条件下,对芝麻品种‘郑芝98N09’的灌浆特性及灌浆期籽粒中内源激素含量变化进行了研究,为芝麻高产优质高效栽培及品质育种提供理论依据。结果表明:(1)第9～17节位芝麻籽粒干物质率最高;下部(8节以下)蒴果在灌浆24d时的蒴果鲜重达最大值(1.596g/蒴),27d时籽粒鲜重达最大值(0.318g/蒴),灌浆最快的时期为灌浆15～33d,干物质积累量达籽粒干重的61.75%;中部(9～20节)蒴果在灌浆27d时的蒴果鲜重达最大值(1.622g/蒴),籽粒鲜重也同期达最大值(0.379g/蒴),灌浆最快的时期为灌浆21～36d,干物质积累量达籽粒干重的74.21%;上部(20节以上)蒴果籽粒干物质积累最快的时期为灌浆9～12d和24～27d两个阶段。(2)中部蒴果GA3含量大于下部和上部蒴果,而ABA和IAA的含量则小于下部和上部蒴果;除GA3/ZR比值外,中部蒴果的ABA/GA3、ABA/ZR、GA3/IAA和ZR/IAA比值都小于下部和上部蒴果。(3)较高的ZR含量和较低的ABA/ZR、ABA/GA3、IAA/GA3和IAA/ZR比值利于胚乳细胞分裂、蒴果发育、籽粒库容建成及籽粒干物质充实。(4)单一激素含量与不同部位蒴果单蒴粒重均达显著或极显著负相关关系,内源激素相互间的关系对下部蒴果粒重增加影响较小,适当提高IAA/ZR、ABA/GA3、IAA/GA3比值,能显著提高中部和上部蒴果的单蒴籽粒干重。     

不同粒型小麦品种内源GA3和ABA含量变化及其与源库的关系

小麦大粒品种籽粒和旗叶中的GA3 含量高于小粒品种 ,而ABA含量低于小粒品种 ,其变化均为单峰曲线 ;但大粒品种籽粒和旗叶中的GA3 的峰值高于小粒品种 ,而ABA的峰值均低于小粒品种 ,而且大粒品种籽粒中ABA出现峰值的时间比小粒品种晚。大粒品种旗叶中GA3 /ABA与光合速率呈显著正相关 (r =0 .884 0 ) ,籽粒中GA3 /ABA与籽粒灌浆速率呈显著正相关 (r =0 .90 70 ) ,籽粒与旗叶中的GA3 /ABA相关不显著 ,而小粒品种籽粒与旗叶中的GA3 /ABA相关达极显著水平 (r =0 .95 98 )     

温光敏雄性不育小麦BNS幼穗发育中的内源激素变化

为探讨温光敏雄性不育小麦BNS育性与内源激素的关系,该研究以BNS不育株和可育株的叶片、幼穗和花药为研究材料(以鲜重计),在雌雄蕊分化期(Ⅰ)到三核期(Ⅵ)之间分期取材。采用酶联免疫法测定生长素(IAA)、赤霉素(GA)和脱落酸(ABA)的含量。结果显示:(1)在发育过程中,不育株IAA含量(33～95ng/g)显著低于可育株(57～112ng/g);不育株ABA、GA含量分别为48～129ng/g、3～14ng/g,可育株分别为77～132ng/g、4～11ng/g,大部分时期不育株显著低于可育株。(2)在雌雄蕊分化期,幼穗不育株IAA和GA含量分别为33.85ng/g和7.13ng/g,可育株分别为50.55ng/g和11.84ng/g,不育株IAA和GA含量均显著低于可育株。(3)在幼穗发育期内,不育株IAA/ABA、IAA/GA和ABA/GA分别为0.4～1.1、4.3～15和7～20,可育株为0.5～0.9、4.3～11.5和7.3～13,与可育株相比,不育株中激素比例浮动较大,表现比例失调。研究表明,BNS幼穗发育中激素的比例失调是雄性不育的形成原因之一,而雌雄蕊分化期的IAA、GA的含量下降可能促进BNS雄性不育的发生。     

氮素形态对小麦花后不同器官内源激素含量的影响

采用盆栽方法,研究了酰胺态氮、铵态氮和硝态氮对小麦(Triticum aestivum)花后根系、旗叶和籽粒内源激素IAA、GA₃、ABA和ZR含量的影响。结果表明,小麦不同器官的内源激素含量对3种氮素形态的响应不同。氮素形态调节籽粒灌浆是通过根系、旗叶和籽粒中内源激素的协同作用而实现的。酰胺态氮与硝态氮处理相比,小麦花后5~15 d,旗叶GA₃含量、籽粒IAA和ABA含量较高,籽粒灌浆速率(Grain-filling rate, GFR)较高;花后15~25 d,根系GA₃含量、旗叶IAA和GA₃含量、籽粒ABA含量较高,籽粒IAA含量较低,GFR较低。铵态氮与硝态氮处理相比,小麦花后5 d,籽粒ZR含量较高;花后15 d前后,籽粒IAA、ABA含量较低,GFR较低;花后20~25 d,根系ZR、GA₃含量较低,旗叶IAA、GA₃含量较低,ABA含量较高,籽粒ABA、GA₃含量较低,IAA含量较高,GFR较高。铵态氮比硝态氮处理的小麦籽粒粒重显著增加。铵态氮和酰胺态氮处理比硝态氮处理增产显著。建议在‘豫麦49’施肥时,使用铵态氮或酰胺态氮并配施硝化抑制剂。     

气调和乙烯对梅果叶绿素和内源激素含量的影响

本文研究了在 ( 2 5± 1 )℃下 ,气调包装和乙烯吸收剂处理对采后青梅果实叶绿素含量、内源激素IAA ,GA3,ABA含量和乙烯释放量的影响及它们之间的关系。结果表明 :气调包装果实叶绿素含量最高 ,其次是乙烯吸收剂处理的 ;各处理中气调包装果实的乙烯释放量始终很低 ,GA3含量较高 ,IAA和ABA含量则较低 ;对照果实的则相反 ,乙烯释放量很高 ,IAA和ABA含量较高 ,而GA3含量较低。乙烯吸收剂处理的处于二者之间。气调包装可以维持果实较高的GA3水平 ,降低ABA含量 ,保持较高的GA3/ABA值 ,抑制IAA和乙烯的生成 ,延缓梅果叶绿素的降解。     

柑橘果实生长发育过程中果实不同部位的4种内源激素含量变化的研究

以单性结实的国庆1号温州蜜柑和自花结实的华农本地早橘为材料,研究了果实生长发育过程中果实不同部位的吲哚乙酸(IAA)、脱落酸(ABA)、赤霉素(GA1/3)和玉米素核苷(ZR)含量的变化。结果表明:(1)国庆1号果皮IAA、GA1/3和ZR含量在幼果阶段均相对较高,随后果皮和果肉IAA含量均趋下降,而在果实膨大期内果肉ABA和果皮、果肉GA1/3、ZR含量均出现上升峰值,果实成熟采收时果皮和果肉ABA含量均明显回升。(2)华农本地早种子、果皮和果肉IAA及其种子ABA含量均在果实膨大期内出现明显峰值,在幼果阶段至果实膨大初期内种子GA1/3和ZR含量均居较高并出现明显上升,对应的果皮、果肉4种内源激素水平均相对较低且变幅小。还就两结实类型柑橘果实生长发育与其内源IAA、ABA、GA1/3和ZR含量动态的关系进行了讨论。     

无花果花芽分化与内源激素含量的关系

在‘布兰瑞克’无花果花芽分化形态学研究的基础上,对花芽分化期无花果新梢第7或第8节位花芽中的玉米素核苷(ZRs)、脱落酸(ABA)、赤霉素(GA1 3)、生长素(IAA)4种内源激素含量的变化进行了探讨。结果表明,在无花果花芽分化阶段,GA1 3和IAA初期含量较高,后快速下降,后期稳定在较低水平;ZRs和ABA在初期含量较低,后大幅提高,后期稳定在较高水平。可见,较高水平的内源ZRs、ABA和较低水平的内源GA1 3、IAA,以及较高的ABA/IAA、ABA/GA1 3、ZRs/GA1 3和ZRs/IAA比值有利于无花果花芽分化。     

植物生长调节剂影响沙田柚内源激素水平的研究

研究了植物生长调节剂优康唑和CPPU对沙田柚生理落果期间幼果和新梢叶片内源IAA、GA1 3和ABA水平的影响.研究结果表明:优康唑处理降低新梢叶片内源IAA和GA1 3水平,提高细胞分裂素含量.优康唑对叶片ABA含量和(IAA GA1 3 CTKs)/ABA比值影响不明显;优康唑处理下幼果IAA、GA1 3和ABA含量均有不同程度的下降,以GA1 3下降幅度最大.果实中CTKs含量和CTKs/ABA比例上升,结合优康唑和CPPU促进沙田柚座果的效应,提示细胞分裂素对座果有重要作用,而CTKs/ABA比例升高有助于缓解生理落果;CPPU处理降低果实ABA含量,提高果实CTKs水平和CTKs/ABA比值.这可能是CPPU促进座果和果实膨大的生理基础.     

南方砂梨返花过程中内源激素含量变化及其与秋季返花的关系

为探讨花芽内源激素含量变化与返花的关系,以砂梨品种‘丰水’、‘翠冠’为材料,研究了砂梨采果后返花过程中花芽内源激素(IAA、GA3、ABA)含量变化,以及早期落叶和秋季返花特征。结果表明:(1)在采果后至返花过程中,两个品种梨花芽中内源激素IAA和GA3含量都呈逐渐缓慢下降趋势;花芽ABA含量的动态变化成升-降-升的"S"曲线。(2)花芽返花受3种激素的动态平衡控制,花芽IAA/ABA、GA3/ABA和(IAA+GA3)/ABA值变化趋势均呈相似的"S"形曲线,IAA/ABA、GA3/ABA和(IAA+GA3)/ABA值增加,花芽返花;比值降低,花芽逐渐步入休眠期。(3)砂梨的落叶率与返花率呈极显著正相关关系,花芽中IAA/ABA比值与砂梨落叶率和返花率相关系数分别为0.805、0.774,相关性均达到显著水平。研究认为,梨返花与早期落叶密切相关,受花芽内源激素IAA、GA3、ABA动态平衡控制;早期落叶降低了花芽中ABA的含量,从而使花芽内生长促进型激素占主导地位,阻止自然休眠的花芽进入休眠或促使进入浅休眠部分花芽解除休眠,所以出现秋季返花现象。     

Hormones in the grains in relation to sink strength and postanthesis development of spikelets in rice

Inferior spikelets usually exhibit a slower grain filling rate and lower grain weight than superior spikelets in a rice (Oryza sativa L.) panicle. This study investigated whether the variations in grain filling between the two kinds of spikelets were attributed to their sink strength and whether the sink strength was regulated by the hormonal levels in the grains. Using two field-grown rice genotypes, the division rate of endosperm cells, hormonal levels in the grains, and grain weight of both superior and inferior spikelets were determined during the grain filling period. The results showed that superior spikelets had dominance over inferior spikelets in endosperm cell division rate and cell number, grain filling and grain weight. Changes in zeatin (Z) and zeatin riboside (ZR) contents paralleled and were very significantly correlated with the cell division rate and cell number. Cell division rate and the content of indole-3-acetic acid (IAA) in the grains were also significantly correlated. Gibberellin (GAs; GA₁+ GA₄) content of the grains was high but ABA levels were low at the early grain filling stage. ABA increased substantially during the linear phase of grain growth and was very significantly correlated with grain dry weight during this period. Application of kinetin at 2 through 6 days post anthesis (DPA) significantly increased cell number, while spraying ABA at 11 through 15 DPA significantly increased the grain filling rate. The results suggest that differences in sink strength are responsible for variations in grain filling between superior and inferior spikelets. Both cytokinins and IAA in the grains may mediate cell division in rice endosperm at early grain filling stages, and therefore regulate the sink size of the grain, whereas ABA content correlates with sink activity during the linear period of grain growth.     

Hormones in the grains and roots in relation to post-anthesis development of inferior and superior spikelets in japonica/indica hybrid rice

Grain filling is usually not adequate in later-flowering inferior spikelets in japonica/indica (J/I) hybrid rice (Oryza sativa) although it shows stronger hybrid vigor than indica/indica (I/I) hybrid. This study investigated the potential causes by examining changes in zeatin (Z) + zeatin riboside (ZR), indole-3-acetic acid (IAA), gibberellins (GAs, GA₁ + GA₄), and abscisic acid (ABA) in spikelets and roots during the grain filling period. The inferior spikelets of J/I hybrid exhibited low rate of endosperm cell division and slow grain filling. During the early grain filing period, they had less Z + ZR, IAA, and ABA, but more GAs, than the earlier-flowering superior spikelets. If compared to the inferior spikelets of the I/I hybrid, the J/I inferior spikelets also had less Z + ZR, IAA, and ABA. Rates of endosperm cell division and grain filling were positively and significantly correlated with Z + ZR and ABA contents in both grains and roots or IAA in grains, whereas not significantly correlated with GAs either in grains or roots or IAA in roots. Applications of kinetin, IAA, or ABA to spikelets, or kinetin and ABA to roots, enhanced cell division and grain filling in the inferior spikelets. Results suggest that low contents of cytokinins and ABA in both grains and roots and low contents of IAA in grains may result in the poor filling of inferior spikelets in the J/I hybrid.     

Grain filling pattern and cytokinin content in the grains and roots of rice plants

Grain filling patterns and their relationships withzeatin (Z), zeatin riboside (ZR), indole-3-acetic acid(IAA) and gibberellin (GA) contents in the grains androots during grain development were examined in sixrice (Oryza sativa L.) genotypes grown in thefield and in water culture. Three grain fillingpatterns based on the filling rate of superior andinferior spikelets were observed, i.e., fastsynchronous: all spikelets started filling early andfast at the early filling stage; slowsynchronous: all spikelets filled slowly at the earlyfilling stage and reached the maximum filling ratelate; and asynchronous: superior spikeletsstarted filling and reached the maximum filling ratemuch earlier than the inferior ones. The order ofgrain filling percentage in the three types of grainfilling patterns was: fast synchronous >asynchronous > slow synchronous. Changes in Z + ZRcontents in the superior and inferior spikelets wereassociated with the grain filling patterns. Grainfilling percentage was significantly correlated withZ + ZR contents in the grains and roots at the earlyand middle grain filling stages. IAA and GA(GA¹ + GA³ + GA⁴)contents in the grains and roots were notsignificantly correlated with grain fillingpercentage. The results suggest that cytokinins in thegrains and roots during the early phase of graindevelopment play an important role in regulating grainfilling pattern and consequently influence grainfilling percentage.     

Growth characteristics and endosperm structure of superior and inferior spikelets of indica rice under high-temperature stress

Heat stress severely reduces rice yield and quality; however, differences between the superior, early-flowering and inferior, later-flowering spikelets of indica rice in response to high-temperature stress during grain filling remain unclear. This study investigated the effects of high temperature (HT, 33.6/20.7 °C day/night) on growth, endosperm structure, and hormone and polyamine content of superior and inferior spikelets of heat-sensitive (SG-1) and heat-tolerant (HHZ) indica cultivars. The HT decreased fertilization rate, caused earlier grain filling, and reduced duration of grain filling, thus resulting in decreased grain mass and a poor endosperm structure. In addition, soluble sugar and sucrose content increased, and starch synthesis decreased by HT at the early stage of grain filling. The HT increased polyamine [spermidine (Spd) and spermine (Spm)] and abscisic acid (ABA) content, but reduced zeatin (Z) + zeatin riboside (ZR) and indole-3-acetic acid (IAA) content in the grains. Such effects were more apparent in the inferior than superior spikelets; however, the inferior spikelets of SG-1 were more affected than those of HHZ. At the middle grain filling stage, HT produced little difference between the two cultivars. Our results suggest that the poor development of inferior spikelets of SG-1 under the HT could be attributed, at least in part, to the changed content and ratios of free polyamines [putrescine (Put), Spd, and Spm] and phytohormones (Z+ZR, IAA, and ABA) and the conversion efficiency of sucrose into starch.     

Post-anthesis development of inferior and superior spikelets in rice in relation to abscisic acid and ethylene

The purpose of this study was to test the hypothesis that the interaction between abscisic acid (ABA) and ethylene may be involved in mediating the post-anthesis development of spikelets in rice (Oryza sativa L.). Two rice genotypes were field-grown, and the changes of ABA, ethylene, and 1-aminocylopropane-1-carboxylic acid (ACC) levels in spikelets during grain filling and their relationships with endosperm-division and grain-filling rates were investigated. The results showed that earlier-flowering superior spikelets exerted dominance over later-flowering inferior spikelets in endosperm cell-division and grain-filling rates. The two genotypes behaved the same. Later-flowering spikelets had higher levels of ethylene and ACC than earlier-flowering spikelets. The ethylene evolution rate was significantly and negatively correlated with the cell division and grain filling rates. By contrast to ethylene, later-flowering spikelets contained a lower ABA content/concentration and showed a low content ratio of ABA to ACC than earlier-flowering ones. The cell-division and grain-filling rates were significantly and positively correlated with both ABA contents and the ratio of ABA to ACC. Application of cobalt ion (inhibitor of ethylene synthesis) or ABA at an early grain-filling stage significantly increased endosperm cell division rate and cell number, grain-filling rate, and grain weight of inferior spikelets. Application of ethephon (an ethylene-releasing agent) or fluridone (an inhibitor of carotenoid synthesis) had the opposite effect. The results suggest that antagonistic interactions between ABA and ethylene mediate endosperm cell-division and grain-filling in rice. A higher ratio of ABA to ethylene in rice spikelets is required to maintain a faster grain-filling rate.     

水稻结实过程中穗不同部位谷粒中内源激素的动态变化

水稻（ＯｒｙｚａｓａｔｉｖａＬ．）结实期间,穗上部谷粒的粒重比穗下部谷粒的高,灌浆前期的增重速率比穗下部谷粒的高,在整个灌浆过程中增重速率的变化比穗下部谷粒的快。利用ＥＬＩＳＡ方法对穗上部谷粒和穗下部谷粒中各种内源激素含量的分析表明,在灌浆过程中,谷粒中未检测出ｉＰＡｓ;在穗上部谷粒和穗下部谷粒中,ＡＢＡ和ＧＡ(１＋３)的含量的最大值出现的时间分别与穗上部谷粒和穗下部谷粒增重最快的时间基本一致,无论穗上部谷粒还是穗下部谷粒中,ＩＡＡ的含量基本上均呈下降趋势;ＧＡ(４＋７)的含量是先上升、后下降、再上升;在结实的前中期,谷粒中ＡＢＡ、ＧＡ(１＋３)的含量基本上均是穗上部谷粒高于穗下部谷粒。探讨了各种激素在谷粒灌浆过程中的作用及从激素的角度探讨了穗上部谷粒比穗下部谷粒结实性好的原因。     

Polyamine and ethylene interactions in grain filling of superior and inferior spikelets of rice

This study was to test the hypothesis that polyamines (PAs) and ethylene and their interactions may be involved in mediating the post-anthesis development of spikelets in rice (Oryza sativa L.). Six rice cultivars differing in grain filling rate were field-grown, and the changing patterns of PAs and ethylene levels in rice spikelets during the filling and their relations with grain filling rates were investigated. The results showed that inferior spikelets had much greater ethylene evolution rate and 1-aminocylopropane-1-carboxylic acid (ACC) concentration than superior spikelets. Opposite to ethylene production, superior spikelets showed much higher free-spermidine (Spd) and free-spermine (Spm) concentrations than inferior spikelets. Grain filling rate was very significantly and negatively correlated with ethylene evolution rate and ACC concentration, whereas positively correlated with free-Spd and free-Spm concentrations and with the ratio of free-Spd or free-Spm to ACC. Application of Spd, Spm, or aminoethoxyvinylglycine (an inhibitor of ethylene synthesis by inhibiting ACC synthesis) to panicles at the early grain filling stage significantly reduced ethylene evolution rate and ACC concentration, while significantly increased Spd and Spm concentrations, grain filling rate and grain weight of inferior spikelets. Application of ACC, ethephon (an ethylene-releasing agent), or methylglyoxal-bis (guanylhydrazone) (an inhibitor of Spd and Spm synthesis) showed the opposite effects. The results suggest that antagonistic interactions between PAs (Spd and Spm) and ethylene may be involved in mediating grain filling. A higher ratio of free-Spd or free-Spm to ethylene in rice spikelets could enhance grain filling.